Coronary Artery Disease is the term used to describe blockages that form in the blood vessels (coronary arteries) that supply the heart muscle. Atherosclerosis, which is the buildup of cholesterol and fat within the blood vessel wall and within the lumen of the blood vessel, is the underlying problem. This buildup in the vessel wall and within the blood vessel lumen can restrict blood flow. This restricted blood flow is what causes the symptoms of angina or chest pain.
It is important to understand that atherosclerosis in a generalized process in patients. If it affects the blood vessels of the heart it is called coronary artery disease; however, this same process can affect blood vessels in other parts of the body and lead to symptoms and problems such as stroke if the vessels in the brain are affected, and peripheral vascular disease (PVD) if the blood vessels in the leg are affected. This PVD can cause leg pain, especially with exercise.
The exact mechanism that leads to the formation of these blockages and why the sometimes become "unstable" is complex. It is clear that some individuals are at higher risk than others for the development of CAD and heart disease. The factors which increase a person's risk for developing atherosclerosis, and in particular coronary artery disease, include diabetes, high blood pressure, high cholesterol, smoking and a family history of early cardiac disease in immediate relatives. There are potentially other risk factors including low HDL (good cholesterol). Obesity can also increase the chances of a person developing CAD, and other related health problems.
Fortunately, coronary artery disease and atherosclerosis in general is largely preventable with management of risk factors and a healthy lifestyle. The ability to "reverse" coronary artery disease is present. With aggressive risk factor management and a healthy lifestyle this can be kept "stable" and the chances of coronary artery disease leading to progressive symptoms or heart attach can be significantly diminished.